diff mbox series

[v5,06/13] bisect--helper: reimplement `bisect_next` and `bisect_auto_next` shell functions in C

Message ID 20200717105406.82226-7-mirucam@gmail.com (mailing list archive)
State New, archived
Headers show
Series Finish converting git bisect to C part 2 | expand

Commit Message

Miriam R. July 17, 2020, 10:53 a.m. UTC
From: Pranit Bauva <pranit.bauva@gmail.com>

Reimplement the `bisect_next()` and the `bisect_auto_next()` shell functions
in C and add the subcommands to `git bisect--helper` to call them from
git-bisect.sh .

bisect_auto_next() function returns an enum bisect_error type as whole
`git bisect` can exit with an error code when bisect_next() does.

Using `--bisect-next` and `--bisect-auto-next` subcommands is a
temporary measure to port shell function to C so as to use the existing
test suite. As more functions are ported, `--bisect-auto-next`
subcommand will be retired and will be called by some other methods.

Mentored-by: Lars Schneider <larsxschneider@gmail.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
Signed-off-by: Miriam Rubio <mirucam@gmail.com>
---
 bisect.c                 |   6 ++
 builtin/bisect--helper.c | 183 ++++++++++++++++++++++++++++++++++++++-
 git-bisect.sh            |  47 +---------
 3 files changed, 190 insertions(+), 46 deletions(-)

Comments

Junio C Hamano July 17, 2020, 4:54 p.m. UTC | #1
Miriam Rubio <mirucam@gmail.com> writes:

> From: Pranit Bauva <pranit.bauva@gmail.com>
>
> Reimplement the `bisect_next()` and the `bisect_auto_next()` shell functions
> in C and add the subcommands to `git bisect--helper` to call them from
> git-bisect.sh .
>
> bisect_auto_next() function returns an enum bisect_error type as whole
> `git bisect` can exit with an error code when bisect_next() does.
>
> Using `--bisect-next` and `--bisect-auto-next` subcommands is a
> temporary measure to port shell function to C so as to use the existing
> test suite. As more functions are ported, `--bisect-auto-next`
> subcommand will be retired and will be called by some other methods.
> ...
> +static enum bisect_error bisect_next(struct bisect_terms *terms, const char *prefix)
> +{
> +	int no_checkout;
> +	enum bisect_error res;
> +
> +	bisect_autostart(terms);
> +	if (bisect_next_check(terms, terms->term_good))
> +		return BISECT_FAILED;
> +
> +	no_checkout = file_exists(git_path_bisect_head());

The ref API is getting updated so that the 40-hex files whose names
are all capital and ends with _HEAD are being converted from "files
that happen to record 40-hex" to "refs that live at the toplevel
outside refs/ hierarchy".  Checking with

	no_checkout = ref_exists("BISECT_HEAD");

would work in both old and new worlds, hopefully.

Similarly, if the new code you are writing reads directly from
git_path_bisect_head(), write into it, or unlink it, these accesses
should be replaced with calls to refs API (e.g. you already do so in
your bisect_state() helper where you use get_oid() on the refname,
not read from the file).

Please learn to pay attention to your surroundings, or you risk
colliding into other topics in flight.

Thanks.
Junio C Hamano July 25, 2020, 12:19 a.m. UTC | #2
Junio C Hamano <gitster@pobox.com> writes:

> The ref API is getting updated so that the 40-hex files whose names
> are all capital and ends with _HEAD are being converted from "files
> that happen to record 40-hex" to "refs that live at the toplevel
> outside refs/ hierarchy".  Checking with
>
> 	no_checkout = ref_exists("BISECT_HEAD");
>
> would work in both old and new worlds, hopefully.
>
> Similarly, if the new code you are writing reads directly from
> git_path_bisect_head(), write into it, or unlink it, these accesses
> should be replaced with calls to refs API (e.g. you already do so in
> your bisect_state() helper where you use get_oid() on the refname,
> not read from the file).

In the meantime, I have applied the following fix-up on top of these
13 patches, but when the topic gets rerolled (as we are in the
feature freeze before the upcoming release, there is no need to
hurry till the end of the month, though), I'd rather want to see the
new use of file_exists(git_path_bisect_head()) disappear.  As it
stands as a 14-patch series, the series would instead end up with us
making a mistake to introduce new use of git_path_bisect_head() at
step 06/14 and then later realize the mistake and fix it at step
14/14, which would be a waste of time for future readers of the code.

Thanks.

-- >8 --
Subject: SQUASH??? do not add new users of git_path_bisect_head()

---
 builtin/bisect--helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 20d359b2ca..eb3d30389b 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -572,7 +572,7 @@ static enum bisect_error bisect_next(struct bisect_terms *terms, const char *pre
 	if (bisect_next_check(terms, terms->term_good))
 		return BISECT_FAILED;
 
-	no_checkout = file_exists(git_path_bisect_head());
+	no_checkout = ref_exists("BISECT_HEAD");
 
 	/* Perform all bisection computation, display and checkout */
 	res = bisect_next_all(the_repository, prefix, no_checkout);
diff mbox series

Patch

diff --git a/bisect.c b/bisect.c
index db00850065..0864e2a21b 100644
--- a/bisect.c
+++ b/bisect.c
@@ -980,6 +980,12 @@  void read_bisect_terms(const char **read_bad, const char **read_good)
  * the bisection process finished successfully.
  * In this case the calling function or command should not turn a
  * BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND return code into an error or a non zero exit code.
+ *
+ * Checking BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND
+ * in bisect_helper::bisect_next() and only transforming it to 0 at
+ * the end of bisect_helper::cmd_bisect__helper() helps bypassing
+ * all the code related to finding a commit to test.
+ *
  * If no_checkout is non-zero, the bisection process does not
  * checkout the trial commit but instead simply updates BISECT_HEAD.
  */
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 7662ec0ce3..4223af144a 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -8,6 +8,7 @@ 
 #include "run-command.h"
 #include "prompt.h"
 #include "quote.h"
+#include "revision.h"
 
 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
@@ -29,10 +30,17 @@  static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
 	N_("git bisect--helper --bisect-start [--term-{old,good}=<term> --term-{new,bad}=<term>]"
 					     "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
+	N_("git bisect--helper --bisect-next"),
+	N_("git bisect--helper --bisect-auto-next"),
 	N_("git bisect--helper --bisect-autostart"),
 	NULL
 };
 
+struct add_bisect_ref_data {
+	struct rev_info *revs;
+	unsigned int object_flags;
+};
+
 struct bisect_terms {
 	char *term_good;
 	char *term_bad;
@@ -56,6 +64,8 @@  static void set_terms(struct bisect_terms *terms, const char *bad,
 static const char vocab_bad[] = "bad|new";
 static const char vocab_good[] = "good|old";
 
+static int bisect_autostart(struct bisect_terms *terms);
+
 /*
  * Check whether the string `term` belongs to the set of strings
  * included in the variable arguments.
@@ -80,7 +90,7 @@  static int write_in_file(const char *path, const char *mode, const char *format,
 	FILE *fp = NULL;
 	int res = 0;
 
-	if (strcmp(mode, "w"))
+	if (strcmp(mode, "w") && strcmp(mode, "a"))
 		BUG("write-in-file does not support '%s' mode", mode);
 	fp = fopen(path, mode);
 	if (!fp)
@@ -107,6 +117,18 @@  static int write_to_file(const char *path, const char *format, ...)
 	return res;
 }
 
+static int append_to_file(const char *path, const char *format, ...)
+{
+	int res;
+	va_list args;
+
+	va_start(args, format);
+	res = write_in_file(path, "a", format, args);
+	va_end(args);
+
+	return res;
+}
+
 static int check_term_format(const char *term, const char *orig_term)
 {
 	int res;
@@ -449,6 +471,143 @@  static int bisect_append_log_quoted(const char **argv)
 	return res;
 }
 
+static int add_bisect_ref(const char *refname, const struct object_id *oid,
+			  int flags, void *cb)
+{
+	struct add_bisect_ref_data *data = cb;
+
+	add_pending_oid(data->revs, refname, oid, data->object_flags);
+
+	return 0;
+}
+
+static int prepare_revs(struct bisect_terms *terms, struct rev_info *revs)
+{
+	int res = 0;
+	struct add_bisect_ref_data cb = { revs };
+	char *good = xstrfmt("%s-*", terms->term_good);
+
+	/*
+	 * We cannot use terms->term_bad directly in
+	 * for_each_glob_ref_in() and we have to append a '*' to it,
+	 * otherwise for_each_glob_ref_in() will append '/' and '*'.
+	 */
+	char *bad = xstrfmt("%s*", terms->term_bad);
+
+	/*
+	 * It is important to reset the flags used by revision walks
+	 * as the previous call to bisect_next_all() in turn
+	 * sets up a revision walk.
+	 */
+	reset_revision_walk();
+	init_revisions(revs, NULL);
+	setup_revisions(0, NULL, revs, NULL);
+	for_each_glob_ref_in(add_bisect_ref, bad, "refs/bisect/", &cb);
+	cb.object_flags = UNINTERESTING;
+	for_each_glob_ref_in(add_bisect_ref, good, "refs/bisect/", &cb);
+	if (prepare_revision_walk(revs))
+		res = error(_("revision walk setup failed\n"));
+
+	free(good);
+	free(bad);
+	return res;
+}
+
+static int bisect_skipped_commits(struct bisect_terms *terms)
+{
+	int res;
+	FILE *fp = NULL;
+	struct rev_info revs;
+	struct commit *commit;
+	struct pretty_print_context pp = {0};
+	struct strbuf commit_name = STRBUF_INIT;
+
+	res = prepare_revs(terms, &revs);
+	if (res)
+		return res;
+
+	fp = fopen(git_path_bisect_log(), "a");
+	if (!fp)
+		return error_errno(_("could not open '%s' for appending"),
+				  git_path_bisect_log());
+
+	if (fprintf(fp, "# only skipped commits left to test\n") < 0)
+		return error_errno(_("failed to write to '%s'"), git_path_bisect_log());
+
+	while ((commit = get_revision(&revs)) != NULL) {
+		strbuf_reset(&commit_name);
+		format_commit_message(commit, "%s",
+				      &commit_name, &pp);
+		fprintf(fp, "# possible first %s commit: [%s] %s\n",
+			terms->term_bad, oid_to_hex(&commit->object.oid),
+			commit_name.buf);
+	}
+
+	/*
+	 * Reset the flags used by revision walks in case
+	 * there is another revision walk after this one.
+	 */
+	reset_revision_walk();
+
+	strbuf_release(&commit_name);
+	fclose(fp);
+	return 0;
+}
+
+static int bisect_successful(struct bisect_terms *terms)
+{
+	struct object_id oid;
+	struct commit *commit;
+	struct pretty_print_context pp = {0};
+	struct strbuf commit_name = STRBUF_INIT;
+	char *bad_ref = xstrfmt("refs/bisect/%s",terms->term_bad);
+	int res;
+
+	read_ref(bad_ref, &oid);
+	commit = lookup_commit_reference_by_name(bad_ref);
+	format_commit_message(commit, "%s", &commit_name, &pp);
+
+	res = append_to_file(git_path_bisect_log(), "# first %s commit: [%s] %s\n",
+			    terms->term_bad, oid_to_hex(&commit->object.oid),
+			    commit_name.buf);
+
+	strbuf_release(&commit_name);
+	free(bad_ref);
+	return res;
+}
+
+static enum bisect_error bisect_next(struct bisect_terms *terms, const char *prefix)
+{
+	int no_checkout;
+	enum bisect_error res;
+
+	bisect_autostart(terms);
+	if (bisect_next_check(terms, terms->term_good))
+		return BISECT_FAILED;
+
+	no_checkout = file_exists(git_path_bisect_head());
+
+	/* Perform all bisection computation, display and checkout */
+	res = bisect_next_all(the_repository, prefix, no_checkout);
+
+	if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
+		res = bisect_successful(terms);
+		return res ? res : BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND;
+	} else if (res == BISECT_ONLY_SKIPPED_LEFT) {
+		res = bisect_skipped_commits(terms);
+		return res ? res : BISECT_ONLY_SKIPPED_LEFT;
+	}
+	return res;
+}
+
+static enum bisect_error bisect_auto_next(struct bisect_terms *terms, const char *prefix)
+{
+	if (bisect_next_check(terms, NULL))
+		return BISECT_OK;
+
+	return bisect_next(terms, prefix);
+}
+
 static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			const char **argv, int argc)
 {
@@ -691,7 +850,9 @@  int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		BISECT_NEXT_CHECK,
 		BISECT_TERMS,
 		BISECT_START,
-		BISECT_AUTOSTART,
+		BISECT_NEXT,
+		BISECT_AUTO_NEXT,
+		BISECT_AUTOSTART
 	} cmdmode = 0;
 	int no_checkout = 0, res = 0, nolog = 0;
 	struct option options[] = {
@@ -715,6 +876,10 @@  int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 			 N_("print out the bisect terms"), BISECT_TERMS),
 		OPT_CMDMODE(0, "bisect-start", &cmdmode,
 			 N_("start the bisect session"), BISECT_START),
+		OPT_CMDMODE(0, "bisect-next", &cmdmode,
+			 N_("find the next bisection commit"), BISECT_NEXT),
+		OPT_CMDMODE(0, "bisect-auto-next", &cmdmode,
+			 N_("verify the next bisection state then checkout the next bisection commit"), BISECT_AUTO_NEXT),
 		OPT_CMDMODE(0, "bisect-autostart", &cmdmode,
 			 N_("start the bisection if it has not yet been started"), BISECT_AUTOSTART),
 		OPT_BOOL(0, "no-checkout", &no_checkout,
@@ -778,6 +943,18 @@  int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		set_terms(&terms, "bad", "good");
 		res = bisect_start(&terms, no_checkout, argv, argc);
 		break;
+	case BISECT_NEXT:
+		if (argc)
+			return error(_("--bisect-next requires 0 arguments"));
+		get_terms(&terms);
+		res = bisect_next(&terms, prefix);
+		break;
+	case BISECT_AUTO_NEXT:
+		if (argc)
+			return error(_("--bisect-auto-next requires 0 arguments"));
+		get_terms(&terms);
+		res = bisect_auto_next(&terms, prefix);
+		break;
 	case BISECT_AUTOSTART:
 		if (argc)
 			return error(_("--bisect-autostart does not accept arguments"));
@@ -793,7 +970,7 @@  int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 	 * Handle early success
 	 * From check_merge_bases > check_good_are_ancestors_of_bad > bisect_next_all
 	 */
-	if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE)
+	if ((res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) || (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND))
 		res = BISECT_OK;
 
 	return -res;
diff --git a/git-bisect.sh b/git-bisect.sh
index d7a6990c29..809be25424 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -65,8 +65,7 @@  bisect_start() {
 	#
 	# Check if we can proceed to the next bisect state.
 	#
-	get_terms
-	bisect_auto_next
+	git bisect--helper --bisect-auto-next || exit
 
 	trap '-' 0
 }
@@ -119,45 +118,7 @@  bisect_state() {
 	*)
 		usage ;;
 	esac
-	bisect_auto_next
-}
-
-bisect_auto_next() {
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD && bisect_next || :
-}
-
-bisect_next() {
-	case "$#" in 0) ;; *) usage ;; esac
-	git bisect--helper --bisect-autostart
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD $TERM_GOOD|| exit
-
-	# Perform all bisection computation, display and checkout
-	git bisect--helper --next-all $(test -f "$GIT_DIR/BISECT_HEAD" && echo --no-checkout)
-	res=$?
-
-	# Check if we should exit because bisection is finished
-	if test $res -eq 10
-	then
-		bad_rev=$(git show-ref --hash --verify refs/bisect/$TERM_BAD)
-		bad_commit=$(git show-branch $bad_rev)
-		echo "# first $TERM_BAD commit: $bad_commit" >>"$GIT_DIR/BISECT_LOG"
-		exit 0
-	elif test $res -eq 2
-	then
-		echo "# only skipped commits left to test" >>"$GIT_DIR/BISECT_LOG"
-		good_revs=$(git for-each-ref --format="%(objectname)" "refs/bisect/$TERM_GOOD-*")
-		for skipped in $(git rev-list refs/bisect/$TERM_BAD --not $good_revs)
-		do
-			skipped_commit=$(git show-branch $skipped)
-			echo "# possible first $TERM_BAD commit: $skipped_commit" >>"$GIT_DIR/BISECT_LOG"
-		done
-		exit $res
-	fi
-
-	# Check for an error in the bisection process
-	test $res -ne 0 && exit $res
-
-	return 0
+	git bisect--helper --bisect-auto-next
 }
 
 bisect_visualize() {
@@ -213,7 +174,7 @@  bisect_replay () {
 		esac
 	done <"$file"
 	IFS="$oIFS"
-	bisect_auto_next
+	git bisect--helper --bisect-auto-next
 }
 
 bisect_run () {
@@ -310,7 +271,7 @@  case "$#" in
 		bisect_skip "$@" ;;
 	next)
 		# Not sure we want "next" at the UI level anymore.
-		bisect_next "$@" ;;
+		git bisect--helper --bisect-next "$@" || exit ;;
 	visualize|view)
 		bisect_visualize "$@" ;;
 	reset)